Each cell of a lithium-ion battery includes a negative electrode and a positive electrode. The negative electrode may consist of a lithium-ion intercalated, reduced-carbon material dispersed on a copper or nickel substrate. The positive electrode may consist of a lithium metal oxide dispersed on an aluminum substrate. The positive and negative electrodes may be arranged in layers, with an insulating separator placed between them to prevent short circuit. The resulting layered structure may be folded or wound into the desired cell configuration, connected to the external contacts of the cell, wetted with a non-aqueous electrolyte solution, and then sealed in a suitable enclosure.
Generally speaking, the performance and longevity of a lithium-ion cell may depend on the degree to which moisture—viz., water—is excluded from the materials sealed in the cell enclosure. Accordingly, the positive and negative electrode layers may be heated under vacuum to desiccate the electrode materials prior to addition of the electrolyte solution. However, vacuum treatment is costly and time-consuming, and is not easily applicable to continuous—e.g., roll-to-roll processing.
Accordingly, one embodiment of this disclosure provides a method for making a lithium-ion cell. The method includes depositing an electrode material as a coating on a substrate of the lithium-ion cell, irradiating the deposited electrode material with microwave radiation of varying frequency, wetting the irradiated electrode material with a non-aqueous electrolyte solution, and sealing the wetted electrode material in an air-tight enclosure. Another embodiment provides an apparatus for making a lithium-ion cell. The apparatus includes an electrode-material deposition stage, a microwave desiccation stage, a wetting stage, and a sealing stage. The deposition stage is configured to deposit an electrode material as a coating on a substrate of the lithium-ion cell. The desiccation stage includes a microwave emitter configured to irradiate the deposited electrode material with microwave radiation of varying frequency. The wetting stage is configured to wet the irradiated electrode material with a non-aqueous electrolyte solution. The sealing stage is configured to seal the wetted electrode material in an air-tight enclosure.
The statements above are provided to introduce a selected part of this disclosure in simplified form, not to identify key or essential features. The claimed subject matter, defined by the claims, is limited neither to the content above nor to implementations that address any problems or disadvantages referenced herein.